Greetings.
build.xml define required jdk version, like 1.6 or 1.7.
But what about jdk updates? What's batter to use to compile l2j server: jdk with newest update, or jdk with older update, that was released nearly current server release?
Is it matter at all?

You should be able to compile with JDK8. L2J doesn't use any of the new features yet though, because Eclipse stable doesn't support JDK8 yet.

If you have problems, FIRST TRY SOLVING THEM YOURSELF, and if you get errors, TRY TO ANALYZE THEM, and ONLY if you can't help it, THEN ask here.
Otherwise you will never learn anything if all you do is copy-paste!Discussion breeds innovation.

I am interested to hear an info about subversions (updates) to current jdk versions aka 1.6, 1.7.
You are telling me there is no difference which version to use at all.
I am not familiar with java yet, that's why I started to ask.
For example in c++ there is a big difference between a libraries, like 2005, 2008, 2010.
When there is no difference which libraries to use, I see it possible only when:
1. Every newer version have a pack of all previous versions (like Physics for example).
2. Every newer version have the same libraries, which has no sense.

So when you advised me to use jdk 8, the only way I see it normal thing to do - if it works as I describe as a 1st way.
But I prefer to use version required by the source code.
As I said before, I want to hear, which update (subversion) should I use: the newest one or the actual one at the time of source code release (mean old chronicles server releases).
Any extra explanation will be appreciated.

Subversion is not related to Java.
I, personally, have no trouble with SVN 1.8 whatsoever.
Just use JDK8 and SVN 1.8, if you get any problems, write here and we'll solve them.

If you have problems, FIRST TRY SOLVING THEM YOURSELF, and if you get errors, TRY TO ANALYZE THEM, and ONLY if you can't help it, THEN ask here.
Otherwise you will never learn anything if all you do is copy-paste!Discussion breeds innovation.

By subversion of jdk I mean not svn client.
I mean jdk sub-version aka jdk 1.6 u01 - jdk 1.6 u40 for example.
Perhaps I am worried to much about that.
By the info you said I could made conlusion, that the code witch require 1.6 version of jdk could be successfully compiled even by jdk 1.7 - jdk 1.8.
I just used to be precise with the tools versions and choose the most proper one. In most of the cases that's important.

By the info you said I could made conlusion, that the code witch require 1.6 version of jdk could be successfully compiled even by jdk 1.7 - jdk 1.8.

That is true.
Java is backwards-compatible down to 1.5 or even 1.4, afaik.
You can't compile Java 8 code with Java 6, but you can do the opposite.

If you have problems, FIRST TRY SOLVING THEM YOURSELF, and if you get errors, TRY TO ANALYZE THEM, and ONLY if you can't help it, THEN ask here.
Otherwise you will never learn anything if all you do is copy-paste!Discussion breeds innovation.